Nowadays, data storage media such as memory cards used in digital cameras, magnetooptical disks used in digital disk cameras, and the like have dramatically increased capacities, and can record various data files such as movie data, audio data, still image data, and the like. In recent years, an edit function that sorts or combines recorded contents by exploiting random accessibility of such recording medium is attracting attention.
A save method of the edit result can be roughly classified into two methods. In one method, the edit result is reconstructed as new data. In the other method, only reproduction control information such as a reproduction sequence, layout, and the like is recorded, and files are accessed and reproduced in accordance with this reproduction control information in a reproduction mode.
In the former method, since the edit result forms new data, it is difficult to change the edit result after it is recorded. On the other hand, in the latter method, when only a part of a file to be reproduced is designated, it cannot always be displayed continuously with a file reproduced immediately before the designated file part due to file access timings or the like. Also, a file designated to be reproduced may have been erased, and the designated file cannot always be displayed as the reproduction result.
A method disclosed in Japanese Patent Laid-Open No. 2000-187963 may be used to assure reproduction continuity between files. In this invention, since data to be reproduced is designated using a pointer to a reproduction time map table, a file part to be reproduced can be determined in advance. The reproduction time map table in this invention indicates the start position of each MPEG decode unit.
However, with the invention described in the above reference, a description method of reproduction control information has a very limited format, and does not allow flexible description.
For example, as one of description methods of such reproduction control information, SMIL (Synchronized Multimedia Integration Language) is known. With SMIL, all of the reproduction start time, reproduction end time, and reproduction duration can be omitted from a description. However, the aforementioned method cannot handle such reproduction control information.
Even when reproduction control information is described in SMIL, if all of the reproduction start time, reproduction end time, and reproduction duration are omitted, a file to be reproduced must be opened to load data in accordance with the format of that file, and to acquire information of the reproduction duration of the file itself.
However, if that data format is not supported by a player or if the designated file is lost, information of the reproduction duration cannot be acquired.
For this reason, reproduction cannot be made in a sequence according to the reproduction control information, resulting in a failure.
For example, in SMIL, the reproduction start time can be described as a relative time from the reproduction end time of an immediately preceding file. In such description method, if the reproduction duration cannot be acquired, the reproduction start time of a file to be consecutively reproduced after that file cannot be settled.